Apparatus for bending sheet material

ABSTRACT

IN APPARATUS FOR IMPARTING A PREDETERMINED PERMANENT CURVATURE TO SHEET BLANKS, WHICH APPARATUS PROVIDES A PREHEATING ZONE ARRANGED ALONG A FIRST LINE AND A COOLING ZONE ARRANGED ALONG A SECOND LINE PARALLEL TO THE FIRST LINE, THE IMPROVEMENT OF PROVIDING AN ADDITIONAL COOLING ZONE ARRANGED ALONG A THIRD LINE PARALLEL TO THE FIRST LINE AND THE SECOND LINE. TWO BENDING STATIONS ARE PROVIDED, ONE ARRANGED NEAR THE SECOND LINE AND THE OTHER ARRANGED NEAR THE THIRD LINE. BOTH BENDING STATIONS ARE ADJACENT THE END OF THE FIRST LINE IN THE DIRECTION OF MOTION OF TRAYS BEING CONVEYED ALONG ALTERNATIVE CONVEYING PATHS DEFINED BY TRACKS.

Jan. 16, 1973 A. JADIN APPARATUS FOR BENDING SHEET MATERIAL 3 Sheets-Sheet 1 Filed May 26, 1971 INVENTOR And r Jodin I BY {l Jan. 16, 1973 A. JADlN 3,711,265

APPARATUS FOR BENDING SHEET MATERIAL Filed May 26, 1971 5 Sheets-Sheet 2 Bending IINVENTOR Andr Jcdin BY i14 Jan. 16, 1973. JADlN 3,711,2.65

APPARATUS FOR BENDING SHEET MATERIAL Filed May 26, 1971 3 Sheets-Sheet 3 INVENTOR Andr dodin 3,711,265 APPARATUS FOR BENDING SHEET MATERIAL Andre Jadin, Dampremy, Belgium, assignor to Glaverbel S.A., Watermael-Boitsfort, Belgium Filed May 26, 1971, Ser. No. 147,041 Claims priority, application Great Britain, July 29, 1970, 36,766/70 Int. Cl. C031) 23/02 US. Cl. 65-287 11 Claims ABSTRACT OF THE DISCLOSURE In apparatus for imparting a predetermined permanent curvature to sheet blanks, which apparatus provides a preheating zone arranged along a first line and a cooling zone arranged along a second line parallel to the first line, the improvement of providing an additional cooling zone arranged along a third line parallel to the first line and the second line. Two bending stations are provided, one arranged near the second line and the other arranged near the third line. Both bending stations are adjacent the end of the first line in the direction of motion of trays being conveyed along alternative conveying paths defined by tracks.

CROSS-REFERENCE TO A RELATED APPLICATION This application relates to improvements in the invention disclosed and claimed in commonly owned U.S. a plication Ser. No. 147,040, filed May 26, 1971, by Pierre Gallez, entitled Apparatus for Bending Sheet Material, and based on British application Ser. No. 26,612/ 70, filed in Great Britain on June 2, 1970.

BACKGROUND OF THE INVENTION This invention relates to an improved plant for imparting predetermined permanent curvatures to sheet blanks.

The above-cited application describes plants for use in bending sheet blanks of, for example, glass which have blank preheating, bending and cooling zones and which are characterized by the following combination of features:

(1) the preheating and cooling zones are arranged along two abreast parallel lines and the bending zone or zones is or are arranged in the lines or one of them and/or in a bridging position between them;

(2) there is at least one tray in which a blank can be supported while it is subjected to preheating, bending and cooling at the zones and which can be displaced first in one direction along one of the lines and then in the reverse direction along the other of the lines for exposing a blank held in such tray to successive treatments at the zones.

Bending plants having these features afford certain advantages, and notably a saving in space, as compared with conventional plants.

SUMMARY OF THE INVENTION According to the present invention, there is provided an improved plant for use in bending sheet blanks. The plant according to the present invention incorporates alternative bending and cooling zones to which a tray can pass successively from the preheating zone or zones by following a conveying path of opposite hand from that which a tray must follow in order to pass to other bending and cooling zones.

If there are at least two trays, provision of the alternative conveying path enables the throughput capacity of the plant to be almost doubled, with a capital outlay of United States Patent O 3,711,265 Patented Jan. 16, 1973 ice much less than twice the cost of a single conveying path plant. It may be necessary to increase the preheating rate to permit full benefit to be realized from the increased potential capacity due to the pressure of the second tray conveying path.

According to particularly advantageous embodiments of the present invention, a plant is provided which has the following features:

(3) the bending zone, or zones, is in a bridging position between preheating and cooling lines required by feature (1) above and/or in the line of and preceding a cooling zone or zones required by that feature;

(4) in fulfillment of feature (2) above there are at least two trays;

(5) there are alternative bending and cooling zones to which a tray can be advanced from the preheating zone or zones, the alternative cooling zone or zones being arranged in a third line disposed so that the preheating zone or zones is in the middle one of the three lines, and the alternative bending zone or zones being located at the same end of the plant as the other bending zone or zones and in a bridging position between the middle and third lines and/or in the third line preceding the alternative cooling zone or zones.

The provision of the alternative bending and cooling zones is not only useful when it is required substantially to increase the throughput capacity of the plant. One of the alternative bending and/or cooling zones can be set up according to performance specifications different from those for which the other bending and/or cooling zones are designed, so that the different tray conveying paths are suitable for processing different types of sheet blanks. If only one conveying path is available, the bending of a sheet blank of a type which requires a rather protracted bending period involves delay in processing any following sheets which may possibly require a shorter bending period. The provision of the alternative conveying paths makes it possible for such following sheets to be advanced through the plant in such a manner as to utilize at least some of the time which would otherwise be lost.

The different bending operations performed at the bending zones relating to the different tray conveying paths can easily be kept under observation by one man.

Although it is possible for a tray moving from one plant line to another to follow a curved path joining those lines, with each tray turning through in passing from one line to the other, and for the bending zone to be located on the curved path, preference is given to an alternative arrangement wherein the first zone of the reverse or return line in the conveying path followed by a tray is a bending zone which is immediately adjacent, specifically, directly opposite, the preheating zone last along the line in the direction of tray displacement. The tray moves parallel with itself and perpendicularly parallel to the plant lines when transferring from one of such lines to the other.

The addition of the alternative zones, in an alternative reverse direction or return path for the trays, does not preclude the adoption of any of the preferred features relating to tray guidance, to the construction of apparatus at the preheating and cooling zones and to other aspects of the plant design as used with only a single conveying path. The various optional features for a single conveying path plant can, except insofar as they relate to the preheating zone or zones common to the two conveying paths, be adopted in either or both of the conveying paths in a plant according to the present invention.

The following are some of the more important preferred, but optional, features which can be adopted when carrying out the present invention:

(a) the treatment zones are stations at which the respective treatments are performed while the trays are stationary for a required, predetermined treatment period;

(b) there are at least two preheating stations;

(c) there are at least two cooling stations in each conveying path;

(d) each bending station is immediately adjacent the preheating station last along its line in the predetermined direction of tray displacement, to reduce loss of heat from heat generators at such preheating station;

(e) the preheating and bending stations have separate hoods from which heat is radiated downwardly ttor heating blanks while they are held beneath hoods in the trays;

(f) the plant includes means for guiding the trays to follow either of the available routes, the guide means preferably having guide rails, or tracks into which pins depending from the trays intrude, the trays being provided with self-orientating casters, or swivel mounted wheels, which run on, for example, a floor;

(g) there is at least one cooling station where there is some form of hood or cover member restricting or controlling radiant heat and/or cooling air flow into and out of a tray, such hood or cover member being, for

example, a fiat or curved plate which closes off, or al- I most closes ofr", the top of the tray which is standing at the cooling station in question.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic perspective view of part of a plant showing features to be used with the present invention.

FIG. 2 is a schematic top plan layout of a plant according to the present invention.

.FIG. 3 is a schematic perspective detail of a cooling station to be used with the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2 of the drawings, a main structure 1 is shown supporting a number of hoods containing heating means-for example, suitable, known electrical resistance heaters-and reflectors for reflecting heat downwardly through the opening defined in the bottoms orf the hoods. The hoods are located at each of four stations; namely, the three preheating stations and the single bending station labeled as such in FIG. 2. Three of the hoods appear in FIG. lthat is, hoods 2 and 3 which are located at two of the three preheating stations and a hood 4 which is located at a bending station. I

The preheating and bending stations may, as already mentioned, incorporate hood-type heating units. These units may, as known per se, have internal radiant heaters or other known heating means and preferably reflectors which direct the heat downwardly into the trays holding the blanks as these move into position beneath the hoods. Particularly at the bending station, there may be electrical resistance or other known heaters which are independently regulatable so that the heat distribution can be locally adjusted to suit the curvature which is to be imparted to the blanks.

Beneath the main structure 1 there is a, for example, floor track 5 formed by, for example, upwardly opening channel section rails and arranged with respect to the station for defining, for example, a rectangular conveying path. This track 5 serves to guide, for example, a plurality 0t trays 10, into each of which a sheet blank to be bent (not shown) is loaded. The number of trays may range from one tray to at least the number of stations. The manner in which the blanks are supported within the trays is not shown. The manner of support is in accordance with known practice. Briefly described, each blank is supported at its opposed ends on the opposed ends of a former (not shown) the upper surface of which is concavely curved filed in Great Britain on June 2, 1970.

FIG. 2 is a plan layout of a plant according to the present invention. As in similar plan views of single conveying path layouts in the copending application trays 10 located for the time being at the different types of stationspreheating, bending and coolingare distinguished by diiferent cross-hatching.

There are three preheating stations arranged abreast along the middle, or first, of three parallel plant lines.

. Trays 10 holding sheet blanks (not shown) to be bent to a predetermined curvature move along this plant line from left to right as indicated by the middle arrow to carry the blank through the successive preheating stations. On completion of the last preheating stage, each tray 10 can follow either one of two conveying paths. The tray 10 can be moved parallel with itself into the bending station located at the beginning 01E the top return line in the figure and then travel from right to left through the cooling stations of that line, or the tray can be moved parallel with itself into the bending station at the beginning of the bottom return line in the figure and then move from right to left through the abreast cooling stations of that line. After completion of cooling of a bent blank, it can be removed rtrom its tray 10 and this tray 10 can then be reloaded, for example, at the station at the left-hand end of the top or bottom plant line, or at the station at the lefthand end of the middle line. The tray 10 can then be displaced through the same conveying path as before or through the other conveying path.

The alternative conveying paths could, of course, be provided with different numbers of cooling stations than that shown.

Each tray 10 is supported on uprights 12, frame 13, and, for example, swivel mounted wheels 6, and movements of each tray 10 may be elfected manually or automatically in any suitable, known manner. For example, driven entraining members and/or hydraulic or pneumatic piston and cylinder units may be used. The conveying paths of the trays 10 being determined by, for example, floor tracks which are designated 5 in the drawing and are engaged by pins 7 on the trays 10* to guide the trays 10.

Cooling according to the present invention in its second aspect as hereinbefore defined can be carried out at a cooling station or stations equipped with a cover member as shown in FIG. 3. The cover, which is designated 9 has a flat plate held in a known manner to supporting structure (not shown) either horizontally or at an inclination to the horizontal by some predetermined angle (not shown), in a position such that when a tray 10 moves into position beneath the cover member 9, gap or gaps are formed between the tray 10 and the plate 9 through which gap(s) cooling air can flow into the tray 10 as indicated in FIG. 3 by the arrows. That is, the plate is arranged to form a gap or gaps with respect to a tray 10. The cooling action thus achieved is particularly suitable for rapidly cooling thin bent glass sheets.

It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.

I claim:

1. In apparatus for imparting a predetermined permanent curvature to sheet blanks and having, in combination:

(a) means defining a preheating zone arranged alonga first line;

(b) means defining a cooling zone arranged along a second line parallel, and adjacent, to said first line;

() means defining a bending zone arranged adjacent at least one of said preheating and cooling zones;

(d) tray means for holding a sheet blank to be imparted with a predetermined permanent curvature; and

(e) means for supporting, and permitting displacement of, said tray means in a predetermined direction along one of the lines and in the reverse direction along the other of the lines for exposing a blank held in said tray means to successive treatments at said zones;

the improvement comprising means defining an additional cooling zone arranged along a third line parallel to said first line and said second line and on the opposite side of said first line from said second line, said means for permitting displacement of said tray means defining alternative conveying paths along said first line and one of said second line and said third line.

2. Apparatus as defined in claim 1 wherein said zones are constituted by stations, and said tray means remains stationary at each station for a required treatment period.

3. Apparatus as defined in claim 2 wherein there are at least two preheating stations in said preheating zone and at least two cooling stations in each of said cooling zones, at least two stations being arranged along each of the lines.

4. Apparatus as defined in claim 3 wherein there are a plurality of said tray means.

5. Apparatus as defined in claim 4 wherein there are two bending stations, one arranged along said second line and the other arranged along said third line, both of said bending stations being arranged immediately adjacent the last preheating station along said first line in the predetermined direction of displacement.

6. Apparatus as defined in claim 5 wherein said preheating and bending stations each have a separate hood from which heat is radiated downwardly for heating blanks while they are held beneath the hoods in respective tray means.

7. Apparatus as defined in claim 6 wherein said means for permitting displacement of said tray means comprises swivel mounted wheels mounted on said tray means, guide means arranged with respect to said stations for defining said alternative conveying paths, and means mounted on said tray means and arranged to cooperate with said guide means for selectively guiding said tray means about said alternative conveying paths.

8. Apparatus as defined in claim 7 wherein said guide means is constituted by a track, and said means arranged to cooperate with said guide means is constituted by a plurality of pins mounted on said tray means and arranged to selectively engage with said track.

9. Apparatus as defined in claim 8 wherein at least one of said cooling stations comprises a cover member.

10. Apparatus as defined in claim 9 wherein said cover member is a fiat plate arranged to at least partially close oif an opening defined by said tray means and is stationary at said cooling station.

11. Apparatus as defined in claim 5 wherein there are three preheating stations arranged along said first line and three cooling stations arranged along each of said second lines and said third line, said tray means being displaced first along said first line and then along one of said second lines and said third line, and said alternative conveying paths being rectangular.

References Cited UNITED STATES PATENTS 900,281 10/1908 Holmes 104 X 2,646,647 7/1953 Bamford et al 65--288 X 2,761,249 9/1956 Olson et a1. 6558 X 3,250,246 5/1966 Stilley et al 65288 X 3,375,094 3/1968 'McMaster et al. 65104X ARTHUR D. KELLOGG, Primary Examiner US. Cl. X.R. 65104 

